Method and device for executing work consisting of a plurality of steps under computer control

ABSTRACT

A method of executing a plurality of steps that are performed sequentially in temporal order under computer control. Each of the plurality of steps is executed by one of a plurality of terminal computers. When a terminal computer assigned to a step has completed the work in the step and is able to execute the work in the next step, it sends a work completion signal to a central processing computer. The central processing computer receives this work completion signal and prepares a work item notice that indicates that the next step can be started, such that the notice can be displayed on the screen of the terminal computer used for the next step. The terminal computer used for the next step allows the notice displayed on its screen to be clicked to start work on the next step assigned to it.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional of U.S. Ser. No. 10/292,067 filed Nov. 12, 2002,now U.S. Pat. No. 6,823,227, which is a Continuation Application under35 U.S.C. §120 of International Application PCT/JP01/03944 filed May 11,2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of executing a plurality ofsteps that are performed sequentially in temporal order under computercontrol.

2. Background

The design of molds used in the injection molding of plastic and moldsused in the casting of cast parts had previously required skilled workin determining the shape of the cavity used to form the mold from thedesign drawings for the product, and in providing slide cores and loosecores for undercut areas and opening areas. Recently, with theappearance of three-dimensional CAD, it is possible to obtain productdesign values as 3D digital data. If the product design values areobtained as 3D digital data, it is possible to determine the shapes ofmold cavities from that 3D digital data, thereby greatly simplifyingmold design. However, even if mold design is performed using 3D digitaldata, the current situation is such that many items that require thework of skilled workers still remain, including the design of slidecores and loose cores to handle complex product shapes.

One proposal is to divide the design work process into a plurality ofsteps and assign each step by specialty to a different worker, but withsuch a division of labor, it takes time and effort to pass work along,so it is difficult to reduce the number of days required for design. Inaddition, even after the design of the mold is completed, there is noguarantee that the work of preparing numerical control data (NC data)for the fabrication of molds based on the design data, and the work ofmachining the molds will be performed efficiently and without delay.Accordingly, the design and fabrication of molds was a problem thatrequired a large amount of time extending to several months.

In addition, not restricting ourselves to the design and fabrication ofmolds, when any work consisting of a plurality of steps is performedconsecutively in a specific order, the establishment of coordinationamong the various steps is necessary for the work to be performedefficiently.

SUMMARY OF THE INVENTION

The present invention was accomplished in light of the aforementionedcircumstances and has as its fundamental object to provide a methodwhereby, when work consisting of a plurality of steps is performedsequentially, that work can be performed efficiently under computercontrol.

Another object of the present invention is to provide a method ofdesigning and fabricating molds that can be performed easily withoutparticular reliance on skilled workers.

In order to achieve the aforementioned objects, the present inventionprovides a method whereby work consisting of a plurality of stepsperformed sequentially is executed under computer control. This methoduses a central processing computer and a plurality of terminalcomputers, where each of the plurality of steps is executed by one ofthe respective terminal computers. Moreover, when one terminal computerassigned to a single step has completed the work in the step assigned toit and is able to execute the work in the next step, that one terminalcomputer sends a work completion signal to the central processingcomputer. The central processing computer receives this work completionsignal and prepares a work item notice that indicates that it ispossible to start the next step that is to be performed next after thisone step such that it can be displayed on the screen of the terminalcomputer used for the next step which is to be assigned to the nextstep. The terminal computer used for the next step allows the work itemnotice displayed on its display screen to be clicked to start work onthe next step assigned to it.

In the event that one step among the plurality of steps includes aplurality of tasks that can be performed in parallel, the centralprocessing computer recognizes from the steps prior to this one stepthat this one step contains a plurality of tasks that can be performedin parallel, and when a work completion signal arrives from the terminalcomputer assigned to the step immediately prior to this one step, it cangenerate a number of work item notices corresponding to the plurality oftasks.

In one preferred embodiment, the present invention provides a method ofperforming the design and fabrication of molds using a centralprocessing computer that stores three-dimensional digital data thatrepresents the product shape, and a plurality of computer terminal unitsconnected to this central processing computer via communication lines.This method comprises: a step of calling up three-dimensional digitaldata describing the product shape from said central processing computerto a first computer terminal unit, performing a three-dimensionaldisplay of the product shape on the screen of said first computerterminal unit, determining a partition line between the upper and lowermold halves based on said screen display, confirming the partitionsurface between the upper and lower mold halves along said partitionline and the mold formation surface shapes of the upper and lower moldhalves, respectively, and sending same to said central processingcomputer where it is saved as digital data, a step of calling upthree-dimensional digital data describing the product shape includingthe digital data formed in said first computer terminal unit from saidcentral processing computer to a second computer terminal unit,performing a three-dimensional display of the product shape on thescreen of said second computer terminal unit, determining the locationswhere slide cores are necessary and the slide direction, and, based onthe size of the slide cores needed at the various locations, selectingones from among a plurality of standard core blocks of different sizesand shapes that are prepared in advance and thus determining the slidecore block to be used, placing this slide core block on the outside ofthe molding surface in said slide direction, and when the slide block isplaced, drawing slide pockets required for the sliding of said slideblock in the upper and lower mold halves, respectively, providing slidecores of a shape determined based on the shape of the molding surface atthe tip in the slide direction of the slide core, and sending same tosaid central processing computer where it is saved as digital data, astep of calling up three-dimensional digital data describing the productshape including the digital data formed in said second computer terminalunit from said central processing computer to a third computer terminalunit, performing a three-dimensional display of the product shape on thescreen of said third computer terminal unit, determining the locationswhere a loose core is necessary, and, based on the size of the loosecores needed at the various locations, selecting ones from among aplurality of standard core blanks of different sizes and shapes that areprepared in advance and thus determining the core blank to be used,placing this core blank at the stipulated position on the moldingsurface, determining the shape of the tip of the loose core based onshape data for the molding surface, and sending same to said centralprocessing computer where it is saved as digital data, a step of callingup three-dimensional digital data describing the product shape includingthe digital data formed in said third computer terminal unit from saidcentral processing computer to a fourth computer terminal unit,performing a three-dimensional display of the product shape on thescreen of said fourth computer terminal unit, determining the locationsof ejector pins, determining the length of the ejector pins from theejector pin locations and the molding surface shape, and sending same tosaid central processing computer where it is saved as digital data, astep of calling up the various data determined above from said centralprocessing computer, preparing numerical control data for moldfabrication based on said data, and sending said numerical control datato said central processing computer where it is saved, and a step ofgetting said numerical control data from said central processingcomputer and fabricating a mold.

In another preferred embodiment, the present invention provides a methodof performing the design and fabrication of molds using a centralprocessing computer that stores three-dimensional digital data thatrepresents the product shape, and a plurality of computer terminal unitsconnected to this central processing computer via communication lines.This method comprises: a step of calling up three-dimensional digitaldata describing the product shape from said central processing computerto a first computer terminal unit, performing a three-dimensionaldisplay of the product shape on the screen of said first computerterminal unit, determining a partition line between the upper and lowermold halves based on said screen display, confirming the partitionsurface between the upper and lower mold halves along said partitionline and the mold formation surface shapes of the upper and lower moldhalves, respectively, and sending same to said central processingcomputer where it is saved as digital data, a step of calling upthree-dimensional digital data describing the product shape includingthe digital data formed in said first computer terminal unit from saidcentral processing computer to a second computer terminal unit,performing a three-dimensional display of the product shape on thescreen of said second computer terminal unit, determining the locationswhere insert cores are necessary, and, based on the size of the insertcores needed at the various locations, selecting ones from among aplurality of standard core blocks of different sizes and shapes that areprepared in advance, providing insert cores of the size and shaperequired, and sending same to said central processing computer where itis saved as digital data, a step of calling up three-dimensional digitaldata describing the product shape including the digital data formed insaid second computer terminal unit from said central processing computerto a third computer terminal unit, performing a three-dimensionaldisplay of the product shape on the screen of said third computerterminal unit, determining the locations of ejector pins, determiningthe length of the ejector pins from the ejector pin locations and themolding surface shape, and sending same to said central processingcomputer where it is saved as digital data, a step of calling up thevarious data determined above from said central processing computer,preparing numerical control data for mold fabrication based on saiddata, and sending said numerical control data to said central processingcomputer where it is saved, and a step of getting said numerical controldata from said central processing computer and fabricating a mold. Inthis case, an insert core may be a slide core or loose core.

In the method according to this preferred embodiment, each of thecomputer terminal units may send work completion signals to the centralprocessing computer when the step assigned to it is completed, and uponreceiving a completion signal for each step, the central processingcomputer may prepare a work item notice that indicates that it ispossible to start the next step that is to be performed next after thisone step such that it can be displayed on the screen of the terminalcomputer which is to be assigned to the next step. The terminal computerassigned to the next step may allow the displayed work item notice to beclicked to start work on the next step assigned to it. The step offorming digital data for cores may include the work of preparing digitaldata for a plurality of cores, and the central processing computer maybe able to display a number of work item notices corresponding to thenumber of cores on the same number of computer terminal units.

The step of preparing numerical control data may include the tasks ofpreparing digital data for a plurality of parts, and the centralprocessing computer may be able to display a number of work item noticescorresponding to the number of tasks on the same number of computerterminal units.

In the present invention, a step of calling up three-dimensional digitaldata describing the product shape from said central processing computerto a computer terminal unit, performing a three-dimensional display ofthe product shape on the screen of said first computer terminal unit,using an exposure device to expose ultraviolet curing resin based onsaid three-dimensional digital data to create a stereolithographic modelas a model of the product, and if the product consists of two or moreparts that are assembled, using this stereolithographic model to confirmthat there is no problem with it in the assembled state is performedprior to the step performed by said first computer.

In still another preferred embodiment, the present invention provides anapparatus whereby work consisting of a plurality of steps performedsequentially is executed under computer control, comprising: a centralprocessing computer and a plurality of terminal computers, each of whichexecutes one of said plurality of steps, wherein: when one of saidterminal computers assigned to a single step has completed the work inthe step assigned to it and is able to execute the work in the nextstep, that one terminal computer transmits a work completion signal,said central processing computer receives this work completion signaland prepares a work item notice that indicates that it is possible tostart the next step that is to be performed next after this one stepsuch that it can be displayed on the screen of the terminal computerused for said next step which is to be assigned to the next step, andsaid terminal computer used for the next step allows the work itemnotice displayed on its display screen to be clicked to start work onsaid next step assigned to it.

In still another embodiment, the present invention provides amanufacturing process control apparatus that controls a manufacturingprocess divided into a plurality of steps that are controlled by aplurality of user terminals, comprising: transmitting means that, whenconditions for the execution of one step of said plurality of steps aremet, transmits to the user terminal that controls said one stepinformation (a signal) to the effect that said step can be started, andreceiving means that, when said one step of the plurality of steps iscomplete, receives from the user terminal that controls said one stepinformation (a signal) to the effect that said one step is complete.

Here, the control of steps is defined to include when the user terminalitself executes the work contained within a step, along with when workcontained within that step is performed by other equipment connected tothe user terminal.

Moreover, “when conditions for the execution of one step are met” meanswhen the data required to execute the work contained in that step andother information is all present and usable.

This apparatus preferably further comprises: a first storage means thatstores information required to execute said plurality of steps, wherein:based on information stored in said first storage means, saidtransmitting means determines whether or not the conditions for theexecution of one step of said plurality of steps are met. In addition,when the conditions for the execution of one step are met, saidtransmitting means transmits to the user terminal to execute said onestep information required for the execution of said one step. Moreover,when one step is complete, said receiving means receives from the userterminal that executed said one step the information generated in saidone step, and stores said information in said first storage means.

Moreover, the apparatus preferably comprises: a second storage meansthat stores information to the effect that one step is complete that isreceived by said receiving means, and progress control means thatcontrols the progress of the manufacturing process based on theinformation stored in said second storage means.

In still another embodiment, the present invention provides amanufacturing process control method for controlling a manufacturingprocess divided into a plurality of steps that are controlled by aplurality of user terminals, comprising: a transmitting step whereby,when conditions for the execution of one step of said plurality of stepsare met, information (a signal) to the effect that said step can bestarted is transmitted to the user terminal that controls said one step,and a receiving step whereby, when said one step of the plurality ofsteps is complete, information (a signal) to the effect that said onestep is complete is received from the user terminal that controls saidone step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the front cover of a mobile phonethat could be manufactured by applying the method according to PreferredEmbodiment 1 of the present invention.

FIG. 2 is a perspective view showing the convex portions and concaveportions used to form the upper mold and lower mold after partitioningthe mold in the mold design process executed by applying the methodaccording to Preferred Embodiment 1 of the present invention.

FIG. 3 is a perspective view showing the block determination stage forthe upper mold.

FIG. 4 is a perspective view showing the block determination stage forthe lower mold.

FIG. 5 is a cross-sectional view schematically showing a slide core.

FIG. 6 is a perspective view showing one example of a slide unit.

FIG. 7 is a side view of a slide unit.

FIG. 8 is a perspective view showing the state of slide units placed onthe lower mold block.

FIG. 9 is a cross-sectional view showing the state of a slide unitattached to the lower mold.

FIG. 10 is a cross-sectional view schematically showing a loose core.

FIG. 11 is a perspective view used to describe the process of preparingnumerical control data.

FIG. 12 is a top view of the mold block shown in FIG. 11.

FIG. 13 is a system diagram showing an example of a computer system usedto control the design and fabrication of molds.

FIG. 14 is a system diagram showing the entire process of design andfabrication of molds to which the present invention is applied.

FIG. 15 is a diagram showing one example of a work notice table for aterminal computer assigned to mold design.

FIGS. 16( a)–16(c) show the mold design steps in Preferred Embodiment 1of the present invention, where FIG. 16( a) is a system diagram showingthe entire mold design process, FIG. 16( b) is a system diagram showingthe lower mold block design process, and FIG. 16( c) is a system diagramshowing the upper mold block design process.

FIG. 17 is a system diagram showing the work flow for various parts inmold fabrication.

FIG. 18 is a diagram showing one example of a work notice table for aterminal computer assigned to prepare numerical control data.

FIG. 19 is a diagram showing one example of a work disclosure table fora terminal computer assigned to the mold machining step.

FIG. 20 is a block diagram showing the mold manufacturing process ofPreferred Embodiment 2 of the present invention.

FIG. 21 is a diagram schematically showing the constitution of themanufacturing process control system of Preferred Embodiment 2 of thepresent invention.

FIG. 22 is a diagram showing the contents of the step information tableof the manufacturing process control apparatus of Preferred Embodiment 2of the present invention.

FIG. 23 is a diagram showing the contents of the step control table ofthe manufacturing process control apparatus of Preferred Embodiment 2 ofthe present invention.

FIG. 24 is a diagram showing the contents of the data storage region ofthe manufacturing process control apparatus of Preferred Embodiment 2 ofthe present invention.

FIG. 25 is a diagram showing the contents of the data control table ofthe manufacturing process control apparatus of Preferred Embodiment 2 ofthe present invention.

FIG. 26 is a diagram showing a chart displayed by the progress controlblock of the manufacturing process control apparatus of PreferredEmbodiment 2 of the present invention.

FIG. 27 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks controlled by the first user terminal ofPreferred Embodiment 2 of the present invention.

FIG. 28 is an example of a step information screen.

FIG. 29 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the second userterminal of Preferred Embodiment 2 of the present invention.

FIG. 30 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the third userterminal of Preferred Embodiment 2 of the present invention.

FIG. 31 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the fourth userterminal of Preferred Embodiment 2 of the present invention.

FIG. 32 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the fifth userterminal of Preferred Embodiment 2 of the present invention.

FIG. 33 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the sixth userterminal of Preferred Embodiment 2 of the present invention.

FIG. 34 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the seventh userterminal of Preferred Embodiment 2 of the present invention.

FIG. 35 is a flowchart showing the operation of the manufacturingprocess control system of Preferred Embodiment 2 of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Here follows a description of embodiments of the present invention madewith reference to drawings. We will first describe the design andfabrication of molds used to manufacture a mobile phone cover, to whichthe present invention can be applied.

Preparatory Stage

FIG. 1 is a perspective view showing the shape of the front cover 1 of amobile phone. The cover of a mobile phone consists of the front cover 1shown in FIG. 1 and a back cover (not shown) which fits onto this frontcover 1. Digital design data that represents the shape of the frontcover 1 and the back cover are prepared by a three-dimensional CADprogram. Three-dimensional CAD programs currently in wide use includeCATIA, UG, Pro/E, I-DEAS and others. Any of these three-dimensional CADprograms can be used to design the cover of a mobile phone. As shown inFIG. 1, the front cover 1 has a window hole 2 for attaching a liquidcrystal display, holes 3 for fitting the number buttons, the # buttonand the * button, and holes 4 for other buttons on the front side.Moreover, while this is not shown clearly in FIG. 1, a lateral openingis formed on the side of the front cover 1. A plurality of projectionsand ribs and the like is formed on the back side, and undercuts areformed in a number of places that would be obstacles to releasing fromthe mold when the front cover 1 is manufactured by injection molding ofplastic.

The three-dimensional shape of the front cover 1 shown in FIG. 1 can bedisplayed on a computer screen based on the digital design data. In thepreparatory stage for mold design, ultraviolet curing resin is exposedbased on this digital design data to create a stereolithographic model.Creating a stereolithographic model from ultraviolet curing resin byexposing the ultraviolet curing resin based on three-dimensional digitaldesign data is a known process, so we shall omit any further detaileddescription. In this preferred embodiment, a similar stereolithographicmodel of the back cover is created in addition to the stereolithographicmodel of the front cover 1. Moreover, the fit between thestereolithographic model of the front cover 1 and the stereolithographicmodel of the back cover is checked to confirm that there are no errorsin the design data for the front cover 1 and back cover. This is toavert the possibility of wastefully creating a mold by performing themold design and fabrication process even though there were errors in theproduct design data but they were not noticed.

Once the stereolithographic model is used to confirm that there are noerrors in the product design data, the preparatory stage for mold designis complete.

Determining the Mold Partition Surface and Identifying Mold Blocks

In this preferred embodiment, the first step of mold design isdetermining the mold partition surface, or namely the partition surfacebetween the upper mold and the lower mold. The mold partition surface ismost typically determined by following the line connecting the points onthe furthermost outside edge in the outer shape of the product. Taking aspecific point on the product as the origin O, as shown in FIG. 1, thex-axis is set in the length direction of the product, the y-axis is setin the width direction of the product, and the z-axis is set in thevertical direction, and by representing the points on the outsidesurface of the product through which the mold partition surface passesas coordinates, it is possible to determine the position of the moldpartition surface as coordinates. This mold partition surface can bedisplayed on a screen display showing the shape of the product as acandidate mold partition line or partition line PL displayed in red oranother specific color. One example of this is shown as a partialphantom line in FIG. 1.

In order to prevent the diagram from becoming difficult to see, thepartition line PL is drawn in FIG. 1 separated from the image of theproduct, but on the actual computer screen, it is presented on thethree-dimensional image representing the product. A computer programused to determine the mold partition surface may be constituted so thatit displays not just one but a plurality of candidate partition lines.

If the candidate partition line displayed on the screen is satisfactory,then clicking on the “Accept” button displayed on the computer screensets the plane following the displayed partition line PL as thepartition surface. If the partition line displayed on the screen is notsatisfactory, then clicking on the “Next Candidate” button on the screendisplay displays the second candidate partition line. By displayingseveral candidates in this manner, it is possible to determine the mostpreferable partition line PL.

FIG. 2 is a perspective view showing the formation surface shapes toform the upper mold and lower mold after the determination of thepartition line. In FIG. 2, the front cover 1 which is the product isshown in the center, above which is shown the concave portion 5constituting the molding surface of the upper mold and below which isshown the convex portion 6 constituting the molding surface of the lowermold. The concave portion 5 of the upper mold and the convex portion 6of the lower mold form the molding cavity between them when the upperand lower molds are closed.

Once the partition line PL is determined, the optimal mold blocks forthe dimensions and shape of the concave portion 5 and convex portion 6are automatically determined and displayed on the display screen. FIG. 3is a diagram showing the state in which the concave portion 5 is formedin the mold block 7 of the upper mold. FIG. 4 is a diagram showing thestate in which the convex portion 6 is formed in the mold block 8 of thelower mold. The determination of the mold blocks 7 and 8 for the upperand lower molds is performed by selecting from blocks of severaldifferent sizes and shapes the ones of the most suitable size and shape.

Placement of Slide Cores

If the product has holes in its side walls or other portions with shapesthat hinder removal of the part from the mold, a slide core must beplaced at that position. FIG. 5 illustrates the concept of the slidecore. A molding cavity 9 is formed between the concave portion 5 of theupper mold block 7 and the convex portion 6 of the lower mold block 8,and molten plastic is injected into this molding cavity 9 and cooled andhardened to form a product. Here, if a hole 10 is to be formed in theside wall of the product, a slide 11 is placed such that it can be movedin the direction of the arrow. A core 11 a used to mold the hole isformed on the tip of this slide 11, and this core 11 a protrudes withinthe molding cavity 9. After the product is cooled and hardened, theupper mold block 7 is moved upward, and the slide 11 is moved in thewithdrawal direction so that the product can be removed from the mold.

In this preferred embodiment, one slide core is constituted by a slideunit 12 having the structure shown in FIG. 6 and FIG. 7. In FIG. 6, theslide unit 12 is provided with a slide guide 13 and this slide guide 13is fixed to the lower mold block 8. A moveable member 14 is guided by aguide groove 13 a within the slide guide 13 so that it moves in thedirection indicated by the arrow. The slide 11 is removably fixed to thetip of this moveable member 14. A molding core 11 b of a prescribedshape is formed on the tip of the slide 11. Moreover, the slide unit 12is provided with a locking block 15 fixed to the upper mold block 7. Asis clear from FIG. 7, the locking block 15 has an inclined cam groove 15a that is open at the bottom. The direction of inclination of the camgroove 15 a is the direction such that it is further from the tip of theslide 11 toward the bottom. An inclined cam following member 14 a thatengages the cam groove 15 a of the locking block 15 is formed on theupper surface of the moveable member 14.

Accordingly, in the state in which the upper mold block 7 is moveddownward and fits against the lower mold block 8, the moveable member 14and slide 11 are pushed out in the direction of the molding cavity 9 andthe molding core 11 b on the tip of the slide 11 is inserted to theprescribed position in the molding cavity 9. In addition, when the uppermold block 7 is raised upward, the moveable member 14 and slide 11 movein the withdrawal direction and the molding core 11 b is withdrawn fromthe molding cavity 9.

FIG. 8 shows the state of the mold used to form the mobile phone frontcover 1 shown in FIG. 1 with the slide unit 12 being placed at theprescribed position of the lower mold block 8. The operation consists offirst determining the prescribed size and type of the slide unit 12, andthen moving the cursor to the prescribed position while watching thecomputer's display screen and clicking, thus executing this operationmanually. The program loaded into the computer is constituted such that,when the size and type of the slide unit 12 are determined and theposition is specified, a concave portion 16 for fitting the slide guide13 and a groove 17 for the moveable member 14 and slide 11 to slide inare automatically drawn at the specified position on the lower moldblock 8. The design related to the slide core in the lower mold block 8is completed upon drawing the concave portion 16 for fitting the slideguide 13 and groove 17 for the moveable member 14 and slide 11 to slidein this lower mold block 8.

The design of the slide unit 12 is performed by a different operation.Standard parts are used for the slide guide 13, moveable member 14 andlocking block 15 in the slide unit 12. To wit, several slide units withdifferent sizes, shapes and types are prepared, and the most appropriateone is selected manual depending on the size and position of the moldingcore 11 b required to mold the product. The result of this selection isalso used to form the concave portion 16 and groove 17 in the lower moldblock 8 described above. In the design of the slide unit 12, thecombination of slide guide 13, moveable member 14 and locking block 15is specified from among the standard parts. Moreover, the element forthe slide 11 is selected to be of a size and shape such that it canengage the moveable member 14. Next, a molding core 11 b of theprescribed shape and size is formed on the tip of this element. Themolding core 11 b is formed by computer processing based on informationfrom design data for the front cover 1 which is the product.

FIG. 9 shows a cross section with the slide unit 12 incorporated intothe mold.

Placement of Loose Cores

Loose cores or similar molding cores are placed at those portions of themold corresponding to undercut areas of the product. FIG. 10 is across-sectional view schematically showing one example of a loose core.A molding cavity 9 is formed between the concave portion 5 of the uppermold block 7 and the convex portion 6 of the lower mold block 8.Products obtained by the cooling and hardening of molten plastic thatfills this molding cavity 9 may need to have an undercut 18. If left asis, this undercut 18 would hinder removal of the part from the moldafter molding. The structure shown in FIG. 10 is one example of a loosecore 20 adopted as a countermeasure thereto. The loose core 20 isprovided with a long, thin rod-shaped core member 19, and on this coremember 19 is formed a convex portion 19 a corresponding to the undercut18 along with the molding surface 19 b in the vicinity.

Upon the lower mold block 8 is formed a guide surface 21 that inclinestoward the interior above the position corresponding to the loose core20. The back surface of the loose core 20 is placed along the guidesurface 21 of the lower mold block 8.

Below the lower mold block 8 is placed a moveable plate 22 with gaps inthe up and down direction with respect to this lower mold block 8 suchthat it is able to move in the up and down direction. The core member 19has its lower edge linked to the moveable plate 22 by a pin linkage.

FIG. 10 shows the mold in the closed state. Molten plastic is injectedinto the molding cavity 9, cooled and hardened and then it is removedfrom the mold. In order to facilitate removal from the mold, an ejectorpin 23 is attached to the moveable plate 22. At the time of removal fromthe mold, the upper mold block 7 is first moved upward. Next, when themoveable plate 22 is moved upward, the molded article is pushed upwardby the ejector pin 23 and separated from the molding convex portion 6 ofthe lower mold block 8. At this time, the core member 19 of the loosecore 20 also moves upward together with the molded article. The coremember 19 moves along the guide surface 21 of the lower mold block 8, soits convex portion 19 a and molding surface 19 b separate from themolded article and move inward, and thus the molded article is removedcompletely from the mold.

The design of the core member 19 of the loose core 20 is also achievedby specifying the appropriate one from among a plurality of standardunits of different sizes and types prepared in advance as the coremember elements, and then forming the convex portion 19 a and moldingsurface 19 b of the stipulated shape. The design data for the convexportion 19 a and molding surface 19 b can be prepared based on the datafor the product shape shown in FIG. 1.

Once the size and type of the core member 19 of the loose core 20 aredetermined, and its position is specified, the stipulated shape of theguide surface 21 is entered upon the lower mold block 8 in the screendisplay and stored as digital design data. In FIG. 8, the symbol 24indicates positions where loose cores 20 are placed.

Placement of Ejector Pins

The ejector pins indicated by the symbol 23 in FIG. 10 must be placed ata plurality of places on the molded article. The ejector pins 23 arepreferably placed at positions that have high rigidity in considerationof the shape of the molded article. For example, in the case of a moldedarticle having the shape shown in FIG. 1, ejector pins 23 are placed atthe four locations indicated by the symbol 23 in FIG. 1. As shown inFIG. 10, the ejector pins 23 have flanges 23 a in the portions incontact with the molded article. Once the positions of the ejector pins23 are determined, their length and the diameter of the flanges 23 a aredetermined automatically from the shape of the molded article. At thesame time, holes 25 corresponding to the ejector pins 23 are formed inthe lower mold block 8 and the data therefor is stored as design data.

Preparation of Numerical Control Data

When the design of the upper mold block 7 and lower mold block 8 of themold and the design of the insert cores including slide cores and loosecores is complete, it is necessary to prepare numerical control data inorder to perform cutting and machining based on this design data. FIG.11 and FIG. 12 are schematic drawings showing one example of thepreparation of numerical control data used to cut the upper mold blockof a mold used to form a product different from the front cover for amobile phone shown in FIG. 1. In this figure, the fine lines are contourlines that indicate points of the same elevation. First, the surface ofthe mold block is cut down to the height of the two contour lines 26equivalent to the highest portion indicated by dashed-dotted lines. Thiscutting is performed by appropriately setting the reciprocating passesof the cutting tool. Next, cutting is performed so that the surface issmoothly contiguous to the position of the contour lines 27 adjacent tothe contour lines 26, and thus the passes of the cutting tool arecontrolled so that cutting is performed by sequentially shifting to theadjacent contour lines. The numerical control data is prepared in orderto determine such passes of the cutting tool and is stored in the formof digital data.

Cutting and Machining

Once the numerical control data for cutting and machining is prepared,this numerical control data is sent to a numerical control cuttingmachine, and the cutting and machining of the mold blocks and materialis performed based on this data.

Control of Steps

In addition to the aforementioned mold design and fabrication steps, allof the steps from the ordering of molds to the completion of fabricationare controlled by the computer system. FIG. 13 shows one example of acomputer system. Referring to FIG. 13, the computer system consists of acentral processing computer 31 and a plurality of terminal units, namelyterminal computers 33 a, 33 b, 33 c, 33 d, . . . , connected to thiscentral processing computer 31 via a communications network 32.

FIG. 14 is a work flowchart showing the main steps from ordering tocompletion of fabrication. In the ordering step 40, a customer ordersthe fabrication of a mold used to manufacture a specific product. Theorder is recorded in a database of the central processing computer 31after adding an order number and other numbers used for control. Asshown in step 41, for the ordered mold, product design data is preparedby three-dimensional CAD in the form of digital data. The digital datafor product design is typically supplied by the customer. As shown instep 42, in parallel with the three-dimensional data preparation step 41a design review is performed. This is used to check to make sure thereis no problem with the product design itself with respect to moldfabrication. The three-dimensional product design data obtained in step41 is sent to the central processing computer 31 of the computer systemand stored in a database.

Step 43 is the step of reading out three-dimensional data, where theproduct design data obtained in step 41 and stored in the centralprocessing computer 31 is read out by the terminal computer 33 a anddisplayed upon its display screen. In step 44, ultraviolet curing resinis exposed based on this read out product design data to create astereolithographic model of the product. As described previously, in thecase that the product consists of two parts, for example, the front andback as in the covers of a mobile phone and these are fitted to eachother to make an assembly, this is the step of confirming that there isno problem with fit when using the design data as is. After astereolithographic model is created, based on these results, a study ofthe mold specifications is performed in step 45, and a molding plan isformulated in step 46. These steps 44, 45 and 46 are performed inparallel and the data may be revised in step 47 if necessary. Therevised data is sent to the central processing computer 31 and stored inits database. At the end of each step, the operator clicks an “End”button or “Send” button on the display screen of the terminal computerto send a work completion signal to the central processing computer 31and the completion of each step is recorded in the central processingcomputer 31.

The central processing computer 31 receives the work completion signalsfrom the terminal computers assigned to the various steps, prepares awork notice table indicating the work to be performed next and arrangesso that the terminal computers 33 can call up the work notice table.FIG. 15 shows one example of a work notice table. The person assigned atask can use a cursor to select the work item assigned to him from thework notice table and clicks to have the data required for that taskcalled up to the terminal computer 33.

In FIG. 14, on orders for which mold design is complete, the ThermoJetstep 49 is performed. The ThermoJet process is one type ofstereolithographic process, where a stereolithographic model of the moldis created based on the data of the completed mold design to confirm theappropriateness of the design. Thereafter, the second design review isperformed in step 50. Next, in the separate-part fabrication stepindicated by step 51, the work of fabricating all of the parts requiredfor the mold is performed. Thereafter, in the mold assembly step 52,mold assembly is performed, where the various appurtenant parts areassembled with the upper mold block and lower mold block, respectively.Finally, in the mold installation step 53, the mold is installed in aninjection molding machine and a test injection molding is performed inthe mold try step 54.

Mold Design

The mold design step 48 consists of a plurality of further subdividedsteps. An example thereof is shown in FIG. 16. In FIG. 16( a), in thefirst stage of mold design, as described previously, the mold partitionsurface determination step 60 is performed (see FIG. 1 and FIG. 2). Oncethe mold partition surface is determined, in the upper and lower blockdetermination step 61, as shown in FIG. 3 and FIG. 4, the upper andlower mold blocks 7 and 8 are determined. Thereafter, as shown in steps62 and 63, the design of the upper mold block 7 and lower mold block 8is started, respectively.

As shown in FIG. 16( b), in the design of the lower block, after step61, step 66 of determining the molding convex portion 6 is performedautomatically and in parallel, in step 67, the slide unit 12 isdetermined. Similarly, in step 68, the placement of the loose core 20 isdetermined and in step 69, the guide surface 21 for the core member 19in the lower mold block 8 is formed. In parallel, the shape of the coremember 19 of the loose core 20 is determined (step 70). These steps areall performed based on the product design data. Thereafter, in step 71,the placement of the ejector pins 23 is determined. Then, the holes 25in the lower mold block 8 that the ejector pins 23 pass through areformed (step 72). In parallel, the length of the ejector pin 23 and thediameter of the flange are determined (step 73).

FIG. 16( c) discloses the design of the upper block 7 which includesstep 64 of determining formation of the molding concave portion 5 and,in step 65, the placement of the slide core 11 a.

In mold design also, at the end of each step, the operator clicks a“Send” button or “End” button on the display screen of the terminalcomputer 33 to send a work completion signal indicating the end of eachwork step to the central processing computer 31. In response to thiswork completion signal, the central processing computer 31 prepares awork notice table indicating the work in mold design that can beperformed next. This work notice table can be called up by the terminalcomputers 33 and displayed on their display screens. FIG. 15 shows thecase of order number 0011. Under this order number, the work noticetable indicates that the slide core placement work indicated by step 65can be performed as the next task. Accordingly, the person assigned tothis work can call up the work notice table on his terminal computer 33and click on the location corresponding to this work, and then performstep 65 for the slide core placement.

Separate-Part Fabrication Step

When the mold design step 48 is complete, the separate-part fabricationstep 51 is performed. Here, the central processing computer 31 receivesinformation from the previously-performed mold design step 48,determines the number of parts required for mold fabrication andprepares a number of work flow-lines corresponding to the number ofparts. FIG. 17 shows one example thereof. In FIG. 17, the centralprocessing computer 31 prepares work notice tables for the terminalcomputers 33 assigned to the preparation of numerical control data inorder to prepare numerical control data for the various parts consistingof the front cover 1, lower mold block 8, slide core No. 1, slide coreNo. 2, loose core No. 1, loose core No. 2 and the moveable plate. FIG.18 is an example of such a work notice table for the one of the terminalcomputers 33 assigned to the preparation of numerical control data.These work notice tables can be called up on the one of the terminalcomputers 33 assigned to the preparation of numerical control data, andthe operator can call up any of the various work notice tables on histerminal computer 33 and click to start on the work.

In this preferred embodiment of the present invention, within thesystem, it is possible to automatically prepare lines on which theinformation required for each of a plurality of parts flows, so there isno need to prepare in advance a large number of work lines anticipatinga large number of parts. Moreover, these work lines are automaticallydeleted when the work steps are complete.

Referring to FIG. 17, regarding the upper mold block 7, in step 75 thenumerical control (NC) data for the cutting and machining of this uppermold block 7 is prepared. When the preparation of numerical control datais complete, the work completion signal is sent from the terminalcomputer 33 to the central processing computer 31, and the centralprocessing computer 31 prepares a cutting and machining work noticetable that indicates that cutting and machining work is possible.Similarly, regarding the lower mold block 8, slide core No. 1, slidecore No. 2, loose core No. 1, loose core No. 2 and moveable plate, thenumerical control data for the cutting and machining is prepared. Whenthe preparation of numerical control data is complete, the workcompletion signal is sent from the terminal computer 33 to the centralprocessing computer 31, and the central processing computer 31 preparesa cutting and machining work notice table that indicates that cuttingand machining work is possible. FIG. 19 shows an example of a worknotice table for a terminal computer 33 assigned to machining work.

The operator assigned to mold machining operates his terminal computer33 to call up the work notice table and performs the machining andfinishing of the upper mold block 7 using a numerical control machinebased on the numerical control data prepared in step 75. This work isindicated in FIG. 17 as steps 76 and 77, respectively. Thereafter, theupper mold block 7 thus fabricated is measured in step 78 and the uppermold block fabrication work is all complete. When the upper mold blockfabrication work is complete, a work completion signal is sent from theassigned terminal computer 33 to the central processing computer 31.Work on parts other than the upper mold block 7 can also be performed inparallel, so each time the work of preparing numerical control data, ormachining, finishing and measuring parts is completed, a work completesignal is sent from the respective assigned terminal computer 33 to thecentral processing computer 31.

When the central processing computer 31 has received a measurementcompletion signal for all of the parts, it determines that theseparate-part machining steps are all complete and prepares work noticetables for the mold assembly step 52 which is the next step. At thistime, the work flow-lines for all of the parts are deleted. The worknotice tables can be called up on the terminal computers 33 assigned tothe mold assembly step 52, and the operator assigned to mold assemblycan call up the work notice table on his terminal computer 33 and startthe work of mold assembly. When the mold assembly step 52 is complete, awork completion signal is sent from the assigned terminal computer 33 tothe central processing computer 31.

Similarly, the mold installation step 53 and mold try step 54 areperformed, thereby completing all of the mold fabrication work.

Here follows a description of the manufacturing process control systemas Preferred Embodiment 2 of the present invention, with reference toFIG. 20 through FIG. 35.

We shall first describe the manufacturing process that is controlledusing the manufacturing process control system according to thispreferred embodiment. As shown in FIG. 20, the manufacturing processthat is controlled using the manufacturing process control systemaccording to this preferred embodiment is a mold fabrication processused in the molding of the covers of mobile phones and the like. Thismanufacturing process is divided into seven steps: the moldspecification determination step P1 in which the mold specifications areprepared, the mold design step P2 in which the shape data for the coreand cavity is prepared, the core NC data preparation step P3 in whichnumerical control data for machining cores (core NC data) is prepared,the cavity NC data preparation step P4 in which numerical control datafor machining the cavity (cavity NC data) is prepared, the coremachining step P5 in which the cores are machined, the cavity machiningstep P6 in which the cavity is machined and the mold assembly step P7 inwhich the cores and cavity are assembled to complete the mold.

As shown in FIG. 20, this manufacturing process must be executed in theorder P1, P2, P3, P5, P7 and P1, P2, P4, P6, P7. Steps P3 and P5, andsteps P4 and P6 can be processed in parallel (overlapping temporally).

Here follows a description of the constitution of the manufacturingprocess control system according to this preferred embodiment. FIG. 21is a diagram schematically showing the constitution of the manufacturingprocess control system of this preferred embodiment. As shown in FIG.21, the manufacturing process control system 200 of this preferredembodiment is provided with a manufacturing process control apparatus(central processing computer) 202 and the first through seventh userterminals 206, 208, 210, 212, 214, 216, 218 connected to thismanufacturing process control apparatus 202 via a communications network204. The communications network 204 may be a network based on leasedlines or the Internet.

The manufacturing process control apparatus 202 is provided with astorage unit 220 that stores various types of data, a receiver 222 thatreceives signals or information from the user terminals, a transmitter224 that transmits signals or information to the user terminals, aprogress controller 226 that controls the progress of steps and adisplay 228.

The manufacturing process control apparatus 202 and the user terminals206–218 each constitutes a computer system consisting of a CPU, memory,hard disk, keyboard, mouse, display and the like. Here follows adescription of the detailed constitution of the various elements.

The first user terminal 206 is a device that executes or controls themold specification determination step P1 (mold specificationpreparation). The first user terminal 206 is constituted such that itreceives from the manufacturing process control apparatus 202 the molddrawings (electronic data) and the like, executes step P1 and transmitsto the manufacturing process control apparatus 202 signals to the effectthat step P1 is complete along with the mold specifications (electronicdata) thus prepared.

The second user terminal 208 is a device that executes or controls themold design step P2 (core and cavity shape data preparation, or namelyCORE and CAVI shape data preparation). The second user terminal 208 isconstituted such that it receives from the manufacturing process controlapparatus 202 the mold specifications and the like prepared in theprevious step, executes step P2 and transmits to the manufacturingprocess control apparatus 202 signals to the effect that step P2 iscomplete along with the core shape data and cavity shape data thusgenerated.

The third user terminal 210 is a device that executes or controls thecore (CORE) NC data preparation step P3 (core NC data generation). Thethird user terminal 210 is constituted such that it receives from themanufacturing process control apparatus 202 the core shape data preparedin the previous step, executes step P3 and transmits to themanufacturing process control apparatus 202 signals to the effect thatstep P3 is complete along with the core NC data thus generated.

The fourth user terminal 212 is a device that executes or controls thecavity (CAVI) NC data preparation step P4 (cavity NC data generation).The fourth user terminal 212 is constituted such that it receives fromthe manufacturing process control apparatus 202 the cavity shape dataprepared in the previous step, executes step P4 and transmits to themanufacturing process control apparatus 202 signals to the effect thatstep P4 is complete along with the cavity NC data thus generated.

The fifth user terminal 214 is a device that controls the core (CORE)machining step P5 (core machining), connected to a machining center 230that performs core machining. The fifth user terminal 214 is constitutedsuch that it receives from the manufacturing process control apparatus202 the core NC data generated in the previous step P3, transmits thiscore NC data to the machining center 230 and causes the machining center230 to perform core machining. Then it transmits to the manufacturingprocess control apparatus 202 signals to the effect that step P5 iscomplete along with the core machined article number (CORE machinedarticle No.) attached to the machined core (core machined article).

The input of the core machined article number may be performed using akeyboard or other input device, or it may be performed by applying barcodes to the core machined articles (or parts prior to machining) andusing a bar code reader provided on the fifth user terminal 214 ormachining center 230 to read these bar codes. By using a bar code readerand bar codes, the actual object (core machined article) and information(core machined article number) can be easily associated. The fifth userterminal 214 may also be made as a single unit with the machining center230.

The sixth user terminal 216 is a device that controls the cavity (CAVI)machining step P6 (cavity machining), connected to a machining center232 that performs cavity machining. The sixth user terminal 216 isconstituted such that it receives from the manufacturing process controlapparatus 202 the cavity NC data generated in the previous step P4,transmits this cavity NC data to the machining center 232 and causes themachining center 232 to perform cavity machining. Then it transmits, tothe manufacturing process control apparatus 202, signals to the effectthat step P6 is complete along with the cavity machined article number(CAVI machined article No.) attached to the machined cavity (cavitymachined article).

The input of the cavity machined article number may be performed using akeyboard or other input device, or it may be performed by applying barcodes to the cavity machined articles (or parts prior to machining) andusing a bar code reader provided on the sixth user terminal 216 ormachining center 232 to read these bar codes. By using a bar code readerand bar codes, the actual object (cavity machined article) andinformation (cavity machined article number) can be easily associated.The sixth user terminal 216 may also be made as a single unit with themachining center 232.

The seventh user terminal 218 is user terminal that controls the moldassembly step P7. The seventh user terminal 218 is constituted such thatit receives from the manufacturing process control apparatus 202 thecore and cavity machined article number generated in the previous stepsP5 and P6, and the operator can refer to these machined article numbersand execute the mold assembly of core and cavity (P7). Then it transmitsto the manufacturing process control apparatus 202 the product number(product No.) attached to the assembled product (mold).

Note that the input of this product number may be performed by applyingbar codes to the assembled product (mold) and using a bar code readerprovided on the seventh user terminal 218 to read these bar codes. Byusing a bar code reader and bar codes, the actual object (productassembled from the core and cavity) and information (product number) canbe easily associated.

The storage unit 220 of the manufacturing process control apparatus 202has a step information table 220 a, step control table 220 b, datastorage region 220 c and data control table 220 d.

The step information table 220 a stores the work content of each of theaforementioned seven steps P1 through P7, respectively, along withinformation required to execute that work content.

Specifically, as shown in FIG. 22, the work content of the moldspecification determination step P1 is the preparation of moldspecifications, and the information required to execute this work is thedrawings, so they are associated with each other and stored as itemsrelated to the mold specification determination step P1 in the stepinformation table 220 a. In addition, the work content of the molddesign step P2 is the preparation of core shape data and the preparationof cavity shape data, and the information required to execute this workis the mold specifications, so they are associated with each other andstored as items related to the mold design step P2. In addition, thework content of the core NC data preparation step P3 is the preparationof core NC data, and the information required to execute this work isthe core shape data, so they are associated with each other and storedas items related to the core NC data preparation step P3. In addition,the work content of the cavity NC data preparation step P4 is thepreparation of cavity NC data, and the information required to executethis work is the cavity shape data, so they are associated with eachother and stored as items related to the cavity NC data preparation stepP4.

In addition, the work content of the core machining step P5 is the coremachining, and the information required to execute this work is the coreNC data, so they are associated with each other and stored as itemsrelated to the core machining step P5. In addition, the work content ofthe cavity machining step P6 is the cavity machining, and theinformation required to execute this work is the cavity NC data, so theyare associated with each other and stored as items related to the cavitymachining step P6. Furthermore, the work content of the mold assemblystep P7 is the mold assembly of core and cavity, and the informationrequired to execute this work is the core machined article number andcavity machined article number, so they are associated with each otherand stored as items related to the mold assembly step P7.

The step control table 220 b is a table used to control which of therespective molds machined in this manufacturing process have proceededto which step, organized by order number (order No.).

The example of the step control table 220 b shown in FIG. 23 indicatesthat the manufacturing processes for the six products (molds) with ordernumbers 1–6 are controlled by the manufacturing process controlapparatus 202, further showing which work step has been completed oneach of the molds. Specifically, this step control table 220 b currentlystores information indicating that the product with order number 1 hascompleted the steps up to the cavity machining step P6, the product withorder number 2 has completed the steps up to the cavity NC datapreparation step P4, the product with order number 3 has completed thesteps up to the core NC data preparation step P3, the product with ordernumber 4 has completed the steps up to the mold design step P2, whilethe product with order number 5 has completed only the moldspecification determination step P1, and the product with order number 6has not completed any steps.

The data storage region 220 c is a region where the information (data)required to execute the aforementioned work steps is stored by product(order number). To wit, the data storage region 220 c stores the productdrawings which are information required to perform the moldspecification determination step P1, the mold specifications which aregenerated in the mold specification determination step P1 and are theinformation (data) required to execute the mold design step P2, the coreshape data and cavity shape data which are generated in the mold designstep P2 and are the information required to execute the core NC datapreparation step P3 and cavity NC data preparation step P4, the core NCdata which are generated in the core NC data preparation step P3 and arethe information (data) required to perform the core machining step P5,and the cavity NC data which are generated in the cavity NC datapreparation step P4 and are the information (data) required to performthe cavity machining step P6.

In the example shown in FIG. 24, the data storage region 220 c storesthe drawings of product numbers 1–6, the mold specifications of theproducts with order numbers 1–5, the core shape data and cavity shapedata of the products with order numbers 1–4, the core NC data of theproducts with order numbers 1–3 and the cavity NC data of the productswith order numbers 1–2.

The data control table 220 d is a table that indicates where theinformation (data) required to execute the various steps is stored inthe data storage region 220 c. In the example shown in FIG. 25, the datacontrol table 220 d stores the location (file name) in the data storageregion 220 c of the drawings for each of the products (molds) with ordernumbers 1–6, the location (file name) in the data storage region 220 cof the mold specifications for each of the products (molds) with ordernumbers 1–5, the location (file name) in the data storage region 220 cof the core shape data for each of the products (molds) with ordernumbers 1–4, the location (file name) in the data storage region 220 cof the cavity shape data for each of the products (molds) with ordernumbers 1–4, the location (file name) in the data storage region 220 cof the core NC data for each of the products (molds) with order numbers1–3, the location (file name) in the data storage region 220 c of thecavity NC data for each of the products (molds) with order numbers 1 and2, and the location (file name) in the data storage region 220 c of thecore NC data for the product (mold) with order number 1. In addition, inthis preferred embodiment, the data control table 220 d stores the coremachined article number and cavity machine article number of the productwith the order number 1. Moreover, if a product number generated by themold assembly step P7 is present, this product number is also stored.

The receiver 222 is constituted so that when the aforementioned stepsare completed, a signal to the effect that the step is complete and theinformation generated in that step are received from the user terminalthat executed that step. Moreover, the signals to the effect that thestep is complete is stored in the step control table 220 b and elsewhereas information to the effect that the step is complete, and the addressthereof is stored in the data control table 220 d.

The transmitter 224 is constituted such that when information requiredfor the execution of the next step is generated or input, it transmitsto the user terminal that is to execute the next step a signal to theeffect that the step is to be started and the information required forthat step.

To wit, when the receiver 222 receives information to the effect that acertain step is complete, or when some new information is stored in thestorage unit 220, or other events occur, the transmitter 224 performs alookup in the required information column of the step information table220 a, and checks for information required to perform a certain step.Next, the transmitter 224 performs a lookup of the data control table220 d and checks to see if that required information is stored in thedata storage region 220 c. If the required information is already storedin the data storage region 220 c, then the transmitter 224 determinesthat all the information required to perform that step is present, andsends to the user terminal controlling that step a signal to the effectthat the step can be started (or to the effect that the step is to bestarted) together with the information required to perform that step.

For example, if the drawings which are the information required toperform the mold specification determination step P1 are stored in thedata storage region 220 c, the transmitter 224 transmits to the firstuser terminal 206, which executes the mold specification determinationstep P1, a signal to the effect that the mold specificationdetermination step P1 can be started (or to the effect that it is to bestarted) together with the drawings which are the information requiredto perform the work contained in the mold specification determinationstep P1.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the mold specification determination step P1 iscomplete and the mold specifications which are the information generatedby the mold specification determination step P1 are received by thereceiver 222 and these mold specifications are stored in the datastorage region 220 c, a signal to the effect that the mold design stepP2 can be started (or is to be started) is transmitted to the seconduser terminal 208, which executes the mold design step P2, along withthe mold specifications which is the information required to perform themold design step P2.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the mold design step P2 is complete and the coreshape data which is the information generated by the mold design step P2are received by the receiver 222 and these mold specifications arestored in the data storage region 220 c, a signal to the effect that themold design step P2 can be started (or is to be started) is transmittedto the second user terminal 208, which executes the mold design step P2,along with the mold specifications which is the information required toperform the mold design step P2.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the mold design step P2 is complete and the coreshape data which is the information generated by the mold design step P2are received by the receiver 222 and this core shape data is stored inthe data storage region 220 c, a signal to the effect that the core NCdata preparation step P3 can be started (or is to be started) istransmitted to the fourth user terminal 212, which executes the core NCdata preparation step P3, along with the core shape data which is theinformation required to perform the core NC data preparation step P3.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the mold design step P2 is complete and the cavityshape data which is the information generated by the mold design step P2are received by the receiver 222 and this cavity shape data is stored inthe data storage region 220 c, a signal to the effect that the cavity NCdata preparation step P4 can be started (or is to be started) istransmitted to the fourth user terminal 212, which executes the cavityNC data preparation step P4, along with the cavity shape data which isthe information required to perform the cavity NC data preparation stepP4.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the core NC data preparation step P3 is complete andthe core NC data which is the information generated by the core NC datapreparation step P3 are received by the receiver 222 and this core NCdata is stored in the data storage region 220 c, a signal to the effectthat the core machining step P5 can be started (or is to be started) istransmitted to the fifth user terminal 214, which controls the coremachining step P5, along with the core NC data which is the informationrequired to perform the core machining step P5.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the cavity NC data preparation step P4 is completeand the cavity NC data which is the information generated by the cavityNC data preparation step P4 are received by the receiver 222 and thiscavity NC data is stored in the data storage region 220 c, a signal tothe effect that the cavity machining step P6 can be started (or is to bestarted) is transmitted to the sixth user terminal 216, which controlsthe cavity machining step P6, along with the cavity NC data which is theinformation required to perform the cavity machining step P6.

In addition, the transmitter 224 is constituted such that, when a signalto the effect that the core machining step P5 and cavity machining stepP6 are complete and the core machined article number and cavity machinedarticle number which are the information generated by the core machiningstep P5 and cavity machining step P6 are received by the receiver 222and this core machined article number and cavity machined article numberare stored in the data storage region 220 c, a signal to the effect thatthe mold assembly step P7 can be started (or is to be started) istransmitted to the seventh user terminal 218, which controls the moldassembly step P7, along with the core machined article number and cavitymachined article number which are the information required to performthe mold assembly step P7.

The progress controller 226 is constituted such that, based on theinformation stored in the step control table 220 b, it controls theprogress of the mold manufacturing process for each of the plurality ofproducts (molds) controlled by the manufacturing process control system200, and displays the progress on the display 228. For example, as shownin FIG. 26, the current plans and results of execution of the sevensteps described above are presented in chart form for the molds withorder numbers 1–6 under control.

Referring to the “Results” rows in the chart of FIG. 26, one can seethat as of the current date (June 14), the mold with order number 1 hascompleted the mold specification determination step P1, mold design stepP2, core NC data preparation step P3, cavity NC data preparation stepP4, core machining step P5 and cavity machining step P6 and is currentlyin the mold assembly step P7. In addition, one can see that the moldwith order number 2 has completed the work contained in moldspecification determination step P1, mold design step P2, core NC datapreparation step P3 and cavity NC data preparation step P4, and it iscurrently in both the core machining step P5 and cavity machining stepP6. One can similarly determine what step the molds with order numbers3–6 are in.

In addition, referring to the “Plans” and “Results” rows of the chart ofFIG. 26, one can see that, for example, the manufacturing process forthe mold with order number 1 is proceeding according to plan, but themanufacturing process for the molds with order number 2 and order number4 is proceeding ahead of schedule.

With the manufacturing process control system 200 of this preferredembodiment constituted as such, the various user terminals areconstituted such that they can display the tasks controlled by each. Forexample, taking the state shown on the chart of FIG. 26 as an example,the various user terminals 206–218 can display the current tasks as ofJune 14 as follows.

FIG. 27 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks controlled by the first user terminal 206which executes the mold specification determination step P1. From thisscreen, one can see that the first user terminal 206 is currentlycontrolling the mold specification determination step P1 of the moldwith order number 6 as an unprocessed task. Here, the operator of thefirst user terminal 206, or namely the operator in charge of the moldspecification determination step P1 may select the “Determine moldspecification” box for order number 6 which is an unprocessed task, anddisplay a step information screen such as that shown in FIG. 28 on thedisplay of the first user terminal 206.

This step information screen contains the name of the step (e.g., themold specification determination step), order number (e.g., 6), thedrawing which is the information required to perform this step and thelocation of that information (e.g., a:

fig

fig6.bmp), indication that the work of this step is the preparation ofmold specifications and the location of the information generated inthis step (e.g., a:

spec

spec6.txt). The operator of the first user terminal 206 refers to such astep information screen while performing the mold specificationdetermination step P1 for order number 6.

FIG. 29 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the second userterminal which controls or executes mold design step P2. Thisunprocessed task list screen is displayed on the display of the seconduser terminal 208. From this screen, one can see that the second userterminal 208 is currently controlling the mold design step P2 of ordernumber 5 as an unprocessed task. Here, the operator of the second userterminal 208, namely the operator in charge of the mold design step P2,may select the “Design mold” box for the mold of order number 5 which isan unprocessed task, and display a step information screen on thedisplay of the second user terminal 208.

This step information screen contains the name of the step, ordernumber, the information required to perform this step and the locationof that information, the work of this step and the location of theinformation generated in this step. The operator of the second userterminal 208 refers to such a step information screen while performingthe mold design step P2 for the mold with order number 5.

FIG. 30 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the third userterminal 210 which controls the core NC data preparation step P3. Thisunprocessed task list screen is displayed on the display of the thirduser terminal 210. From this screen, one can see that the third userterminal 210 is currently controlling the core NC data preparation stepP3 of the mold of order number 4 as an unprocessed task. The operator ofthe third user terminal 210, namely the operator in charge of the coreNC data preparation step P3, may select the “Prepare core NC data” boxfor the mold of order number 4 which is an unprocessed task, and displaya step information screen on the display of the third user terminal 210.The step information screen contains the name of the step, order number,the information required to perform this step and the location of thatinformation, the work contained in this step and the location of theinformation generated in this step. The operator of the third userterminal 210 refers to such a step information screen while performingthe core NC data preparation step P3 for the mold with order number 4.

FIG. 31 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the fourth userterminal 212 which controls the cavity NC data preparation step P4. Thisunprocessed task list screen is displayed on the display of the fourthuser terminal 212. From this screen, one can see that the fourth userterminal 212 is currently controlling the cavity NC data preparationstep P4 of the molds of order numbers 3 and 4 as unprocessed tasks.Here, the operator of the fourth user terminal 212, namely the operatorin charge of the cavity NC data preparation step P4, may select the“Prepare cavity NC data” box for the mold of order number 3 or 4 whichare unprocessed tasks, and display a step information screen on thedisplay of the fourth user terminal 212. This step information screencontains the name of the step, order number, the information required toperform this step and the location of that information, the workcontained in this step and the location of the information generated inthis step. The operator of the fourth user terminal 212 refers to such astep information screen while performing the cavity NC data preparationstep P4 sequentially for the molds with order numbers 3 and 4.

FIG. 32 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the fifth userterminal 214 which controls the core machining step P5. This unprocessedtask list screen is displayed on the display of the fifth user terminal214. From this screen, one can see that the fifth user terminal 214 iscurrently controlling the core machining step P5 of the molds of ordernumbers 2 and 3 as unprocessed tasks. The operator of the fifth userterminal 214, namely the operator in charge of the core machining stepP5, may select the “Machine core” box for order number 2 or 3 which areunprocessed tasks, and display a step information screen on the displayof the fifth user terminal 214. This step information screen containsthe name of the step, order number, the information required to performthis step and the location of that information, the work contained inthis step and the location of the information generated in this step.The operator of the fifth user terminal 214 refers to such a stepinformation screen while performing the cavity core machining step P5sequentially for the molds with order numbers 2 and 3.

FIG. 33 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the sixth userterminal 216 which controls the cavity machining step P6. Thisunprocessed task list screen is displayed on the display of the sixthuser terminal 216. From this screen, one can see that the sixth userterminal 216 is currently controlling the cavity machining step P6 ofthe mold of order number 2 as an unprocessed task. The operator of thesixth user terminal 216, namely the operator in charge of the cavitymachining step P6, may select the “Machine cavity” box for order number2 which is an unprocessed task, and display a step information screen onthe display of the sixth user terminal 216. The step information screencontains the name of the step, order number, the information required toperform this step and the location of that information, the workcontained in this step and the location of the information generated inthis step. The operator of the sixth user terminal 216 refers to such astep information screen while performing the cavity core machining stepP5 sequentially for the mold with order number 2.

FIG. 34 is an example of the unprocessed task list screen which displaysa list of unprocessed tasks currently controlled by the seventh userterminal 218 which controls the mold assembly step P7. This unprocessedtask list screen is displayed on the display of the seventh userterminal 218. From this screen, one can see that the seventh userterminal 218 is currently controlling the mold assembly step P7 of ordernumber 1 as an unprocessed task. The operator of the seventh userterminal 218, namely the operator in charge of the mold assembly stepP7, may select the “Assemble mold” box for order number 1 which is anunprocessed task, and display a step information screen on the displayof the seventh user terminal 218. The step information screen containsthe name of the step, order number, the information required to performthis step and the location of that information, the work contained inthis step and the location of the information generated in this step.The operator of the seventh user terminal 218 refers to such a stepinformation screen while performing the mold assembly step P7 for themold with order number 1.

Here follows a description of the operation of the manufacturing processcontrol system 200 of this preferred embodiment. FIG. 35 is a flowchartshowing the operation of the manufacturing process control system 200.Note that the flowchart of FIG. 35 shows only the processing of a singlemold (product), but when the processing steps on the mold with one ordernumber are complete, each user terminal can perform the same processingsteps on the mold with the next order number.

First, when the drawing which is the information required to perform themold specification determination step P1 is stored in the data storageregion 220 c of the manufacturing process control apparatus 202, asignal to the effect that the mold specification determination step P1can be started (or is to be started) and the drawing which is theinformation required to perform the mold specification determinationstep P1 are sent from the transmitter 224 (S1) and received by the firstuser terminal 206 which controls and executes the mold specificationdetermination step P1 (S2). Next, the operator of the first userterminal 206 performs the preparation of mold specifications which isthe work of the mold specification determination step P1 (S3).

When the mold specification determination step P1 is complete, a signalto the effect that the mold specification determination step P1 iscomplete and the mold specifications which are the information generatedin the mold specification determination step P1 are sent from the firstuser terminal 206 (S4) and received by the receiver 222 (S5). When themold specifications are stored in the data storage region 220 c, asignal to the effect that the mold design step P2 can be started (or isto be started) and the mold specifications which are the informationrequired to perform the mold design step P2 are sent from thetransmitter 224 (S6) and received by the second user terminal 208 whichcontrols and executes the work contained in the mold design step P2(S7). Next, the operator of the second user terminal 208 performs thepreparation of core shape data and the preparation of cavity shape datawhich is the work of the mold design step P2 (S8).

When the mold design step P2 is complete, a signal to the effect thatthe mold design step P2 is complete and the core shape data and cavityshape data which are the information generated in the mold design stepP2 are sent from the second user terminal 208 (S9) and received by thereceiver 222 (S10).

When the core shape data is stored in the data storage region 220 c, asignal to the effect that the core NC data preparation step P3 can bestarted (or is to be started) and the core shape data which is theinformation required to perform the core NC data preparation step P3 aresent from the transmitter 224 (S11) and received by the third userterminal 210 which controls the core NC data preparation step P3 (S12).Next, the operator of the third user terminal 210 performs thepreparation of core NC data which is the work of the core NC datapreparation step P3 (S13).

When the core NC data preparation step P3 is complete, a signal to theeffect that the core NC data preparation step P3 is complete and thecore NC data which is the information generated in the core NC datapreparation step P3 are sent from the third user terminal 210 (S14) andreceived by the receiver 222 (S15).

When the cavity shape data is stored in the data storage region 220 c, asignal to the effect that the cavity NC data preparation step P4 can bestarted (or is to be started) and the cavity shape data which is theinformation required to perform the cavity NC data preparation step P4are sent from the transmitter 224 (S16) and received by the fourth userterminal 212 which controls and executes the cavity NC data preparationstep P4 (S17). Next, the operator of the fourth user terminal 212performs the preparation of cavity NC data which is the work of thecavity NC data preparation step P4 (S18).

When the cavity NC data preparation step P4 is complete, a signal to theeffect that the cavity NC data preparation step P4 is complete and thecavity NC data which is the information generated in the cavity NC datapreparation step P4 are sent from the fourth user terminal 212 (S19) andreceived by the receiver 222 (S20).

When the core NC data is stored in the data storage region 220 c, asignal to the effect that the core machining step P5 can be started (oris to be started) and the core NC data which is the information requiredto perform the core machining step P5 are sent from the transmitter 224(S21) and received by the fifth user terminal 214 which controls thecore machining step P5 (S22). Next, the operator of the fifth userterminal 214 performs the core machining which is the work of the coremachining step P5 (S23). The core machining is performed by themachining center 230 connected to the fifth user terminal 214. When thecore machining is complete, a core machined article number is attachedto the core machined article and this core machined article number isinput to the fifth user terminal 214.

When the core machining step P5 is complete, a signal to the effect thatthe core machining step P5 is complete and the core machined articlenumber which is the information generated in the core machining step P5are sent from the fifth user terminal 214 (S24) and received by thereceiver 222 (S25).

On the other hand, when the cavity NC data is stored in the data storageregion 220 c, a signal to the effect that the cavity machining step P6can be started (or is to be started) and the cavity NC data which is theinformation required to perform the cavity machining step P6 are sentfrom the transmitter 224 (S26) and received by the sixth user terminal216 which controls the cavity machining step P6 (S27). Next, theoperator of the sixth user terminal 216 performs the cavity machiningwhich is the work of the cavity machining step P6 (S28). The cavitymachining is performed by the machining center 232 connected to thesixth user terminal 216. When the cavity machining is complete, a cavitymachined article number is attached to the cavity machined article andthis cavity machined article number is input to the sixth user terminal216.

When the work contained in the cavity machining step P6 is complete, asignal to the effect that the cavity machining step P6 is complete andthe cavity machined article number which is the information generated inthe cavity machining step P6 are sent from the sixth user terminal 216(S29) and received by the receiver 222 (S30).

When the received core machined article number and cavity machinedarticle number are stored in the step control table 220 b, a signal tothe effect that the mold assembly step P7 can be started (or is to bestarted) and the core machined article number and cavity machinedarticle number which are the information required to perform the moldassembly step P7 are sent from the transmitter 224 (S31) and received bythe seventh user terminal 218 which controls the mold assembly step P7(S32). Next, the operator of the seventh user terminal 218 performs themold assembly of the core and cavity which is the work of the moldassembly step P7 (S33). When the mold assembly of the core and cavity iscomplete, a product number is attached to the product (mold) consistingof the core and cavity thus assembled and this product number is inputto the seventh user terminal 218.

When the work contained in the mold assembly step P7 is complete, asignal to the effect that the mold assembly step P7 is complete and theproduct number which is the information generated in the mold assemblystep P7 are sent from the seventh user terminal 218 (S34) and receivedby the receiver 222 (S35). Note that this product is managed by means ofthe product number and shipped.

In addition, the progress of this mold manufacturing process iscontrolled by the progress controller 226 based on the informationcontained in the step control table 220 b, and displayed on the display228 as needed.

The manufacturing process control system 200 according to PreferredEmbodiment 2 described above controls the work contained in the sevensteps P1 through P7 by means of seven user terminals 206 through 218which differ depending on the step, but one user terminal may alsocontrol or execute two or more steps. In addition, one step may also becontrolled or executed by a plurality of user terminals.

In addition, the present invention was described using the design andmanufacture of molds as an example, but the ideas expressed in thepresent invention recited in the claims are not limited to the designand manufacture of molds, but rather they are applicable to any methodby which work consisting of a plurality of steps is executed undercomputer control.

1. A method of performing design and fabrication of molds using acentral processing computer that stores three-dimensional digital datathat represents a product shape and a plurality of computer terminalunits connected to the central processing computer via communicationlines, wherein the method comprises a plurality of work stepssequentially performed in the computer terminal units, wherein saidsteps comprise: (a) a step of calling up three-dimensional digital datadescribing the product shape from the central processing computer to afirst computer terminal unit, performing a three-dimensional display ofthe product shape on a screen of the first computer terminal unit,determining a partition line between upper and lower mold halves basedon said displayed product shape, confirming a partition surface betweenthe upper and lower mold halves along said partition line and moldformation surface shapes of the upper and lower mold halves,respectively, and sending same to the central processing computer whereit is saved as digital data; (b) a step of calling up three-dimensionaldigital data describing the product shape including the digital dataformed in the first computer terminal unit from the central processingcomputer to a second computer terminal unit, performing athree-dimensional display of the product shape on a screen of saidsecond computer terminal unit, determining a first location where aslide core is necessary and a slide direction, and, based on a size ofthe slide core needed at the first location, selecting one from among aplurality of standard slide core blocks of different sizes and shapesthat are prepared in advance and thus determining a slide core block tobe used, placing this slide core block on the outside of a moldingsurface in said slide direction, and when the slide core block isplaced, drawing slide pockets required for sliding said slide core blockin the upper and lower mold halves, respectively, providing the slidecore of a shape determined based on the shape of the molding surface ata tip in the slide direction of the slide core, and sending same to thecentral processing computer where it is saved as digital data; (c) astep of calling up three-dimensional digital data describing the productshape including the digital data formed in the second computer terminalunit from the central processing computer to a third computer terminalunit, performing a three-dimensional display of the product shape on ascreen of the third computer terminal unit, determining a secondlocation where a loose core is necessary, and, based on a size of theloose core needed at the second location, selecting one from among aplurality of standard core blanks of different sizes and shapes that areprepared in advance and thus determining a core blank to be used,placing this core blank at a stipulated position on the molding surface,determining a shape of a tip of the loose core based on shape data forthe molding surface, and sending same to the central processing computerwhere it is saved as digital data; (d) a step of calling upthree-dimensional digital data describing the product shape includingthe digital data formed in the third computer terminal unit from thecentral processing computer to a fourth computer terminal unit,performing a three-dimensional display of the product shape on a screenof the fourth computer terminal unit, determining a location of anejector pin, determining a length of the ejector pin from the determinedejector pin location and a molding surface shape, and sending same tothe central processing computer where it is saved as digital data; (e) astep of calling up various data determined in steps (a) to (d) from thecentral processing computer, preparing numerical control data for moldfabrication based on said data, and sending said numerical control datato the central processing computer where it is saved; and (f) a step ofgetting said numerical control data from the central processing computerand fabricating a mold; wherein each of the computer terminal unitssends a work completion signal to the central processing computer whenit has completed a step assigned to it, and upon receiving the workcompletion signal, the central processing computer prepares a work itemnotice that indicates that it is possible to start a next step such thatthe work item notice can be displayed on a screen of whichever one ofthe plurality of computer terminal units is assigned to the next step,and the computer terminal unit assigned to the next step allows thedisplayed work item notice to be clicked to start work on said nextstep.
 2. The method according to claim 1, wherein: said step of formingdigital data for cores includes preparing digital data for a pluralityof cores, and the central processing computer can display a number ofwork item notices corresponding to the number of said cores on the samenumber of computer terminal units.
 3. The method according to claim 1,wherein: said step of preparing numerical control data includespreparing digital data for a plurality of parts, and the centralprocessing computer can display a number of work item noticescorresponding to the number of said parts on the same number of computerterminal units.
 4. The method according to claim 1, further comprisingthe following steps which are performed prior to step (a): calling upthree-dimensional digital data describing the product shape from thecentral processing computer to a computer terminal unit, performing athree-dimensional display of the product shape on the screen of thefirst computer terminal unit, using an exposure device to exposeultraviolet curing resin based on said three-dimensional digital data tocreate a stereolithographic model as a model of the product, and if theproduct consists of two or more parts that are assembled, using thisstereolithographic model to confirm that there is no problem with it inthe assembled state.
 5. A method of performing design and fabrication ofmolds using a central processing computer that stores three-dimensionaldigital data that represents a product shape and a plurality of computerterminal units connected to the central processing computer viacommunication lines, wherein the method comprises a plurality of worksteps sequentially performed in the computer terminal units, whereinsaid steps comprise: (a) a step of calling up three-dimensional digitaldata describing the product shape from the central processing computerto a first computer terminal unit, performing a three-dimensionaldisplay of the product shape on a screen of the first computer terminalunit, determining a partition line between upper and lower mold halvesbased on said displayed product shape, confirming a partition surfacebetween the upper and lower mold halves along said partition line andmold formation surface shapes of the upper and lower mold halves,respectively, and sending same to the central processing computer whereit is saved as digital data; (b) a step of calling up three-dimensionaldigital data describing the product shape including the digital dataformed in the first computer terminal unit from the central processingcomputer to a second computer terminal unit, performing athree-dimensional display of the product shape on a screen of the secondcomputer terminal unit, determining a first location where an insertcore is necessary, and, based on a size of the insert core needed at thefirst location, selecting one from among a plurality of standard coreblocks of different sizes and shapes that are prepared in advance,providing the insert core of the size and shape required, and sendingsame to the central processing computer where it is saved as digitaldata; (c) a step of calling up three-dimensional digital data describingthe product shape including the digital data formed in the secondcomputer terminal unit from the central processing computer to a thirdcomputer terminal unit, performing a three-dimensional display of theproduct shape on a screen of the third computer terminal unit,determining a location of an ejector pin, determining a length of theejector pin from the determined ejector pin location and a moldingsurface shape, and sending same to the central processing computer whereit is saved as digital data; (d) a step of calling up various datadetermined in steps (a) to (c) from the central processing computer,preparing numerical control data for mold fabrication based on saiddata, and sending said numerical control data to the central processingcomputer where it is saved; and (e) a step of getting said numericalcontrol data from the central processing computer and fabricating amold; wherein each of the computer terminal units sends a workcompletion signal to the central processing computer when it hascompleted a step assigned to it, and upon receiving the work completionsignal, the central processing computer prepares a work item notice thatindicates that it is possible to start a next step such that the workitem notice can be displayed on a screen of whichever one of thecomputer terminal units is assigned to the next step, and the computerterminal unit assigned to the next step allows the displayed work itemnotice to be clicked to start work on said next step.
 6. The methodaccording to claim 5, wherein: said insert core is a slide core.
 7. Themethod according to claim 5, wherein: said insert core is a loose core.8. The method according to claim 5, further comprising the followingsteps which are performed prior to step (a): calling upthree-dimensional digital data describing the product shape from thecentral processing computer to a computer terminal unit, performing athree-dimensional display of the product shape on the screen of thefirst computer terminal unit, using an exposure device to exposeultraviolet curing resin based on said three-dimensional digital data tocreate a stereolithographic model as a model of the product, and if theproduct consists of two or more parts that are assembled, using thisstereolithographic model to confirm that there is no problem with it inthe assembled state is.
 9. The method according to claim 5, wherein:said step of forming digital data for cores includes preparing digitaldata for a plurality of cores, and the central processing computer candisplay a number of work item notices corresponding to the number ofsaid cores on the same number of computer terminal units.
 10. The methodaccording to claim 5, wherein: said step of preparing numerical controldata includes preparing digital data for a plurality of parts, and thecentral processing computer can display a number of work item noticescorresponding to the number of said parts on the same number of computerterminal units.